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Rullich CC, Kiefer J. Chemometric analysis of enantioselective Raman spectroscopy data enables enantiomeric ratio determination. Analyst 2019; 144:5368-5372. [PMID: 31414107 DOI: 10.1039/c9an01205b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In-line determination of the enantiomeric ratio is still a challenge in process analytical technology (PAT). This study combines enantioselective Raman (esR) spectroscopy with partial least-squares regression (PLSR) to determine the enantiomeric fraction of the chiral molecule (5,6)-diphenyl-morpholin-2-one diluted in dimethyl sulfoxide (DMSO) as a proof-of-concept. Morpholinone derivates are potential candidates for pharmaceutical applications. The PLS weights were carefully analyzed in order to avoid misleading regression results, e.g. caused by sample impurities. A suitable PLSR model was found with two components and it was validated by a leave-one-out cross-validation. The enantiomeric fraction ef(+) could be calculated with deviations from the prepared ef(+) in the range of -0.031 and +0.052 from the esR spectra recorded at a half-wave retarder angle of 30.0°.
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Affiliation(s)
- Claudia C Rullich
- Technische Thermodynamik, Universität Bremen, Badgasteiner Str. 1, 28359 Bremen, Germany.
| | - Johannes Kiefer
- Technische Thermodynamik, Universität Bremen, Badgasteiner Str. 1, 28359 Bremen, Germany. and MAPEX Center for Materials and Processes, Universität Bremen, Bibliothekstr. 1, 28359 Bremen, Germany
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2
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Rullich CC, Kiefer J. Principal component analysis to enhance enantioselective Raman spectroscopy. Analyst 2019; 144:2080-2086. [PMID: 30734784 DOI: 10.1039/c8an01886c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Enantioselective Raman (esR) spectroscopy is an innovative technique with a high potential for online process monitoring in chiral media, e.g. in the pharmaceutical industry. A prerequisite for an effective application is to combine the experimental approach with suitable concepts for data analysis. In this work, we present a chemometric approach to analyze the esR spectra recorded in an automatized polarization-resolved Raman set-up. It is demonstrated that the proposed method is capable of distinguishing between the enantiomers of the chiral alcohol 4-methylpentan-2-ol in a fully unsupervised fashion. Furthermore, it is shown that the difficulty of facing only small intensity differences between the esR spectra of the enantiomers can be overcome by feeding difference spectra between the pure enantiomers and the racemate into the principal component analysis (PCA) algorithm. The enantiomers are clearly discriminable along the first principal component.
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Affiliation(s)
- Claudia C Rullich
- Technische Thermodynamik, Universität Bremen, Badgasteiner Str. 1, 28359 Bremen, Germany
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Rullich CC, Kiefer J. Enantioselective Raman spectroscopy (esR) for distinguishing between the enantiomers of 2-butanol. Analyst 2018; 143:3040-3048. [PMID: 29878000 DOI: 10.1039/c8an00705e] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The first experimental application of enantioselective Raman spectroscopy (esR) is demonstrated using the example of the chiral alcohol 2-butanol. Samples of the neat enantiomers and the racemic mixture were analyzed in a self-built Raman set-up. The Raman spectrum allows the discrimination of the chemical species. It is shown that the optical rotation of a Raman peak with a small depolarization ratio can be measured. In addition, without any sample modification, e.g. chiral solvent, the enantiomers are distinguishable at a suitable half-wave retarder angle detecting only the vertically polarized component of the Raman signal.
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Affiliation(s)
- Claudia C Rullich
- University of Bremen, Technische Thermodynamik, Badgasteiner Str. 1, 28359 Bremen, Germany
| | - Johannes Kiefer
- University of Bremen, Technische Thermodynamik, Badgasteiner Str. 1, 28359 Bremen, Germany and University of Bremen, MAPEX Center for Materials and Processes, 28359 Bremen, Germany.
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Mower MP, Blackmond DG. In-Situ Monitoring of Enantiomeric Excess During a Catalytic Kinetic Resolution. ACS Catal 2018. [DOI: 10.1021/acscatal.8b01411] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Matthew P. Mower
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037 United States
| | - Donna G. Blackmond
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037 United States
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Li Q, Wu T, Lai J, Fan Z, Zhang W, Zhang G, Cui D, Gao Z. Diversity of Coordination Modes, Structures, and Properties of Chiral Metal–Organic Coordination Complexes of the Drug Voriconazole. Eur J Inorg Chem 2015. [DOI: 10.1002/ejic.201500741] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Qing Li
- Department of the Key Laboratory of Applied Surface and Colloid Chemistry, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi 710062, P. R. China, http://www.snnu.edu.cn
- Department of the School of Environmental and Chemical Engineering, Xi'an Polytechnic University, Xi'an, Shaanxi 710048, P. R. China, http://www.xpu.edu.cn/
| | - Tao Wu
- Department of Coordination Chemistry Institute and the State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210093, P. R. China http://www.nju.edu.cn/
| | - Jian‐Cheng Lai
- Department of Coordination Chemistry Institute and the State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210093, P. R. China http://www.nju.edu.cn/
| | - Zeng‐Lu Fan
- Department of the School of Environmental and Chemical Engineering, Xi'an Polytechnic University, Xi'an, Shaanxi 710048, P. R. China, http://www.xpu.edu.cn/
| | - Wei‐Qiang Zhang
- Department of the Key Laboratory of Applied Surface and Colloid Chemistry, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi 710062, P. R. China, http://www.snnu.edu.cn
| | - Guo‐Fang Zhang
- Department of the Key Laboratory of Applied Surface and Colloid Chemistry, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi 710062, P. R. China, http://www.snnu.edu.cn
| | - Dan Cui
- Department of the Key Laboratory of Applied Surface and Colloid Chemistry, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi 710062, P. R. China, http://www.snnu.edu.cn
| | - Zi‐Wei Gao
- Department of the Key Laboratory of Applied Surface and Colloid Chemistry, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi 710062, P. R. China, http://www.snnu.edu.cn
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Sato H, Mori Y, Yamagishi A. Conformational change of a chiral Schiff base Ni(ii) complex with a binaphthyl moiety: application of vibrational circular dichroism spectroscopy. Dalton Trans 2013; 42:6873-8. [DOI: 10.1039/c3dt00112a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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7
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Wu T, Zhang XP, You XZ. Stereo-chemical analysis of racemization of a chiral bipyridine. RSC Adv 2013. [DOI: 10.1039/c3ra45645e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Busacca CA, Lorenz JC, Saha AK, Cheekoori S, Haddad N, Reeves D, Lee H, Li Z, Rodriguez S, Senanayake CH. Development of the BIPI ligands for asymmetric hydrogenation. Catal Sci Technol 2012. [DOI: 10.1039/c2cy20337e] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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9
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Busacca CA, Fandrick DR, Song JJ, Senanayake CH. The Growing Impact of Catalysis in the Pharmaceutical Industry. Adv Synth Catal 2011. [DOI: 10.1002/adsc.201100488] [Citation(s) in RCA: 369] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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